1. Field of the Invention
The present invention relates to mechanisms for operating high voltage switches, and more particularly, to a switch operating mechanism that can be uncoupled from the high voltage switches, withdrawn from the equipment enclosure, and exercised or maintained without interrupting the circuit controlled by the high voltage switch.
2. Description of the Prior Art
Drawout type circuit breakers for use in metal enclosed switchgear are well known. The drawout breaker is generally mounted on a wheeled carriage which may be rolled into the bay of the metal enclosure. High voltage power connections to the circuit breaker are made with separable contacts at the rear of the breaker. When the breaker is fully inserted into the bay of the enclosure, the high voltage contacts are engaged and the control wiring contacts to the circuit breaker also are engaged. If maintenance is required to be performed on the circuit breaker or if complete removal from the bay of the enclosure is required to guarantee isolation of the circuits at the controlled point, the entire drawout breaker may be withdrawn completely out of the switchgear. However, if it is desired to exercise the breaker or verify that its control circuits and mechanical functions are intact, it is typical in the art for the breaker to have a so-called test position in which the breaker is withdrawn from its normal position sufficiently to disengage from the high voltage contacts but in which the separable control contacts remain engaged. Thus, in this position the breaker can be operated to open and close without interrupting the high voltage circuit.
Prior switch operating mechanisms such as those which are described in U.S. Pat. No. 3,563,102--Bernatt, et al., issued Feb. 16, 1971, and U.S. Pat. No. 3,980,977--Evans, issued Sept. 14, 1976, both of which are assigned to the same assignee as the present invention, do not provide a means for uncoupling the switch operating mechanism from the high voltage switch to allow the switch operating mechanism to be exercised or maintenance to be performed. Therefore, in order to exercise a prior art switch operating mechanism to verify that the control circuits and mechanical functions are intact it is necessary to operate the high voltage switch and thereby interrupt the high voltage circuits.
It is desirable to incorporate the uncoupling and drawout features of drawout circuit breakers into switch operating mechanisms for high voltage switches. Therefore, it would be a desirable advance in the art to provide a switch operating mechanism such as the one described in the co-pending U.S. patent application entitled "High-Voltage Switch Operating Mechanism," Ser. No. 911,123 filed May 31, 1978, and assigned to the same assignee as the present invention, that incorporates a drawout concept which would permit the switch operating machanism to be exercised without changing the condition of the high voltage switch. It would also be a desirable advance in the art to provide a switch operating mechanism which could be uncoupled from the high voltage switch and withdrawn from the equipment enclosure to provide access for maintenance of the switch operating mechanism.